Scaffold Having Lift Apparatus

ABSTRACT

A lift apparatus includes a ladder assembly having a first ladder end portion and a second ladder end portion extending upwardly from a base framework, each end portion having a pair of upstanding support legs and a plurality of rungs. The lift apparatus includes a platform that is slidably coupled to respective support legs of respective ladder end portions, the platform having a floor surface capable of supporting a person. The lift apparatus include a motorized pulley system operable for raising and lowering the platform relative to the ladder end portions via a controller accessible to the worker while standing on the platform.

BACKGROUND OF THE INVENTION

This invention relates generally to scaffolding devices and, more particularly, to a scaffold having a platform and a motorized pulley assembly that enables a single worker to raise and lower a scaffold platform.

Scaffolding is a temporary structure used to support a work crew and materials to aid in the construction, painting, maintenance, and repair of buildings, bridges and the like. Scaffolds are widely used on site to gain access to heights and areas that would be otherwise hard to access. A common job in construction or painting requires attention at more than a single height and this means that the height of the scaffolding must be raised or lowered. The task of adjusting the height of scaffolding is definitely not trivial. More particularly, this action may require multiple workers to disassemble a portion of the scaffolding or to add another level of scaffolding and then to once again climb upwardly to the work platform. Further, this adjustment may require a single worker to adjust one side and then walk around and adjust the other side. Alternatively, a height adjustment may more workers adjusting the height simultaneously and, in any case, the worker or work crew must again climb the scaffolding to reach the work platform.

Therefore, it would be desirable to have scaffolding that includes a lift apparatus such that a height of a work platform pray be raised or lowered using electric controls operable from the work platform. Further, it would be desirable to have scaffolding that includes a lift apparatus that is raised or lowered motorized mechanics, such as winch and pulley devices. In addition, it would be desirable to have scaffolding that includes a lift apparatus and having a pair of extension ladders that are slidably or telescopically raised or lowered.

SUMMARY OF THE INVENTION

A scaffold lift apparatus according to the present invention includes a ladder assembly having a first ladder end portion and a second ladder end portion extending upwardly from a base framework, each end portion having a pair of upstanding support legs and a plurality of rungs. The lift apparatus includes a platform that is slidably coupled to respective support legs of respective ladder end portions, the platform having a floor surface capable of supporting a person. The lift apparatus include a motorized pulley system operable for raising and lowering the platform relative to the ladder end portions via a controller accessible to the worker while standing on the platform.

Therefore, a general object of this invention is to provide a scaffold lift apparatus for raising and lowering a worker on a scaffold while the worker remains standing on the scaffold.

Another object of this invention is to provide the scaffold lift apparatus, as aforesaid, in which the worker can raise and lower a platform on a scaffold by himself and without the assistance of another person and without dismounting the scaffold.

Still another object of this invention is to provide a scaffold lift apparatus, as aforesaid, having telescopic ladder assemblies on either end portion of the scaffold.

Yet another object of this invention is to provide a scaffold lift apparatus, as aforesaid, which has castor wheels so as to be mobile and portable.

Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a perspective view of a scaffold lift apparatus according to a preferred embodiment of the present invention, illustrated with a platform in a completely lowered configuration;

FIG. 1b is an isolated view on an enlarged scale taken from FIG. 1 a;

FIG. 1c is an isolated view on an enlarged scale taken from FIG. 1 a;

FIG. 2a is a perspective view of the scaffold lift apparatus as in FIG. 1, illustrated with the platform in a partially raised configuration;

FIG. 2b is an isolated view on an enlarged scale taken from FIG. 2 a;

FIG. 3a is an exploded view of the scaffold lift apparatus as in FIG. 1;

FIG. 4a is a perspective view of a base assembly removed from the scaffold lift apparatus of FIG. 1;

FIG. 4b is an isolated view on an enlarged scale taken from FIG. 4 a;

FIG. 5a is an isolated view of a spring-loaded locking pin removed from the scaffold lift apparatus of FIG. 1 with a pin shown in the engaged position and an unlocked configuration;

FIG. 5b is an isolated view of a spring-loaded locking pin removed from the scaffold lift apparatus of FIG. 1 with a pin shown in the retracted position and a locked configuration;

FIG. 6a is a perspective view of a platform removed from the scaffold lift apparatus of FIG. 3 a;

FIG. 6b is an isolated view on an enlarged scale taken from FIG. 6 a;

FIG. 6c is an isolated view on an enlarged scale taken from FIG. 6 a;

FIG. 6d is an isolated view on an enlarged scale taken from FIG. 6 a;

FIG. 6e is an isolated view on an enlarged scale taken from FIG. 6 a;

FIG. 6f is an isolated view on an enlarged scale taken from FIG. 6a ; and

FIG. 7 is an exploded view of the platform as in FIG. 6 a.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A scaffold lift apparatus according to a preferred embodiment of the present invention will now be described in detail with reference to FIGS. 1a to 7 of the accompanying drawings. The scaffold lift apparatus 10 includes a first ladder end portion 20, a second ladder end portion 30, and a platform 40 that may be raised and lowered by a single worker using a motorized pulley lift assembly.

The scaffold lift apparatus 10 includes a base framework 12 (which may be referred to merely as a framework) to which the first and second ladder portions are coupled and from which they extend upwardly. More particularly, the framework 12 includes a front brace 13 and a rear brace 14 that is opposite and parallel to the front brace 13. The front brace 13 and rear brace 14 have linear configurations and have proximal and distal ends, respectively. A first side brace 15 extends between the proximal ends and a second side brace 16 extends between the distal ends of the front and rear braces 13, 14, respectively. Together, the braces may combine to form a base.

A plurality of support pocket fasteners 17 is mounted atop the braces described above. Preferably, a support pocket fastener 17 is attached at each corner or intersection between a respective brace as illustrated in FIG. 4a . Further, each support pocket fastener 17 includes a continuous side wall defining an interior area and an open top through which the interior area is configured to receive a respective leg of a respective ladder end portion as will be described in more detail later. In addition, each support pocket fastener 17 includes a spring-loaded locking assembly having, as the name implies, a spring and a locking device that is configured to lock a leg of a respective ladder end portion in the interior space automatically when the leg is inserted therein. When no leg is inserted, the spring 18 causes a pin 19 to move to a fully engaged position (FIG. 5a ) whereas insertion of a leg into a support pocket fastener 17 biases the pin outwardly (FIG. 5b ). It will be understood that in the biased position, the spring urges the pin to bear against the inserted leg of a ladder portion—thus causing the frictional holding or locking of the leg into the base framework 12. A knob may be coupled to the pin 19 that allows a user to manually bias the spring and pin outwardly so as to release a respective leg from the support pocket fastener 17 (FIGS. 5a and 5b ).

Turning now specifically to the rest of the scaffold, a ladder assembly includes a first ladder end portion 20 and a second ladder end portion 30, the end portions having substantially similar configurations and being positioned opposite one another and being vertically upstanding from respective side braces of the base framework 12 (FIG. 1).

More particularly, the ladder assembly includes a first ladder end portion 20 having a first fixed section 21 and a first variable section 25 movably coupled to the first fixed section 21 and movable between lowered and raised configurations. The first fixed section 21 refers to a pair of legs extending upwardly from the base framework 12 as described above and that are parallel to one another and includes reference to a first plurality of ladder rungs 24 extending between the pair of legs. The pair of legs of the first fixed section 21 may also be referred to as a first upstanding leg 22 and a second upstanding leg 23 of the first fixed section 21. The first plurality of ladder rungs 24 extends horizontally between the pair of legs and is spaced apart in the manner of a ladder.

Similarly, the ladder assembly includes a second ladder end portion 30 having a second fixed section 31 and a second variable section 35 movably coupled to the second fixed section 31 and movable between lowered and raised configurations. The second fixed section 31 refers to a pair of legs extending upwardly from the base framework 12 as described above and that are parallel to one another and includes reference to a second plurality of ladder rungs 34 extending between the pair of legs. The pair of legs of the second fixed section 31 may also be referred to as a first upstanding leg 32 and a second upstanding leg 33 of the second fixed section 31. The second plurality of ladder rungs 34 extends horizontally between the pair of legs and is spaced apart in the manner of a ladder.

Further, the first ladder end portion 20 includes what is referred to as a first variable section 25 because it is slidably movable or telescopically length adjustable relative to the first fixed section 21 from which is depends. The term “variable” refers to having a variable or adjustable height. In other words, the first variable section 25 also includes a pair of upstanding legs that are spaced apart from one another and includes a plurality of rungs 26 extending therebetween (a construction that is substantially similar to the construction of the first fixed section). The legs of the first variable section 25 may be slidably coupled (to the inside or the outside) of respective legs of the first fixed section 21 and may be length adjustable, such as with pins or other fasteners.

In like manner, the second ladder end portion 30 includes what is referred to as a second variable section 35 because it is slidably movable or telescopically length adjustable relative to the second fixed section 31 from which is depends. The term “variable” refers to having a variable or adjustable height. In other words, the second variable section 35 also includes a pair of upstanding legs that are spaced apart from one another and includes a plurality of rungs 36 extending therebetween (a construction that is substantially similar to the construction of the second fixed section). The legs of the second variable section 35 may be slidably coupled (to the inside or the outside) to respective legs of the second fixed section 31 and may be length adjustable, such as with pins or other fasteners.

In an important aspect, the platform 40 is coupled to the first ladder end portion 20 and to the second ladder end portion 30 but is slidably movable along respective legs thereof between lowered and raised configurations as will be described below. But, first, the platform 40 (which may also be referred to as a lift platform) includes a floor surface 41 having a generally flat or planar surface suitable for supporting a standing worker, e.g. a construction worker or painter. Further, the platform 40 includes a platform first end portion 42 having a first pair of upstanding support members upstanding from an end of the floor surface and having a first plurality of ladder rungs 43 extending between the first pair of upstanding support members. Similarly, the platform 40 includes a platform second end portion 44 having a second pair of upstanding support members upstanding from another end of the floor surface and having a second plurality of ladder rungs 45 extending between the second pair of upstanding support members.

Further, the platform includes a platform front section 46 extending between the platform first end portion 42 and the platform second end portion 44. The platform front section 46 include one or more upstanding support braces and at least one front support rail 47 displaced above the floor surface 41 and extending laterally between the platform end portions. The platform front section 46 may also include a gate member 48 that may interrupt the front support rail 47 and have a distal end that is selectively movable between open and closed positions (FIG. 6a ), e.g. for the ingress or egress of a worker. Similarly, the platform 40 may include a platform rear section 49 which may also include upstanding support members (not shown) and at least a rear support rail 49 a displaced above the floor surface 41 and extending laterally between the platform end portions.

In another aspect, the platform 40 may be raised and lowered electromechanically by a single worker actuating one or more pulley assemblies. A first winch assembly 50 may include a first winch motor 51 and a first spool 52 electrically connected to the first winch motor 51 and the first winch assembly 50 is preferably positioned adjacent the first ladder end portion 20. When the first winch motor 51 is energized, a first cord 54 (e.g. a cable, rope, or the like) is wound about the spool or unwound therefrom. Specifically, a proximal end of the first cord 54 is coupled to the first spool 52. Further, the first winch assembly 50 includes a first pulley 53 that may be coupled to an uppermost rung of the first variable section 25 of the first ladder end portion 20 or to another comparable rung or structure. It is understood that the first pulley 53 may also be referred to as an idler wheel or just as a wheel. The first cord 54 is then run around or about the first pulley 53 and has a distal end coupled to a first end of the platform 40. Therefore, when the first winch motor 51 is energized, the first cord 54 is wound about the first spool 52 and the platform 40 is raised by action of the pulley engagement.

Similarly, a second winch assembly 60 may include a second winch motor 61 and a second spool 62 electrically connected to the second winch motor 61 and the second winch assembly 60 is preferably positioned adjacent the second ladder end portion 30. When the second winch motor 61 is energized, a second cord 63 (e.g. a cable, rope, or the like) is wound about the spool or unwound therefrom. Specifically, a proximal end of the second cord 63 is coupled to the second spool 62. Further, the second winch assembly 60 includes a second pulley 64 that may be coupled to an uppermost rung of the second variable section 35 of the second ladder end portion 30 or to another comparable rung or structure. It is understood that the second pulley 63 may also be referred to as an idler wheel or just as a wheel. The second cord 63 is then run around or about the second pulley 63 and has a distal end coupled to a second end of the platform 40. Therefore, when the second winch motor 61 is energized, the second cord 63 is wound about the second spool 62 and the platform 40 is raised by action of the pulley engagement. Preferably, the first and second winch assemblies are actuated simultaneously so that the platform 40 remains level as it is raised or lowered as will be described below in further detail.

Now it will be described how the platform 40 is slidably raised and lowered in relation to the ladder end portions 20, 30. In general, at least one corner of the floor surface 41 of the platform 40 is slidably and in a frictionally coupling to an upstanding leg of the first ladder end portion 20 and, similarly, another corner of the platform 40 is slidably and frictionally coupled to an upstanding leg of the second ladder end portion 30 with respective alignment brackets 70 that allow slidable movement (e.g. raising and lowering). In an embodiment, one of a plurality of alignment brackets 70 may couple a corner of the platform 40 to each upstanding leg, respectively. An alignment bracket 70 may have a configuration that essentially surrounds a respective upstanding leg so that the platform maintains its alignment (longitudinally and laterally) while moving vertically along respective legs.

In a necessary aspect, the scaffold lift apparatus 10 includes a controller 72, which may also be referred to as a control module or a control unit, having at least buttons indicative of raising and lowering the platform, e.g. UP and DOWN. Preferably, the controller includes a casing mounted to or proximate to the platform rear section 49 (FIGS. 6a and 6b ). The controller 72 is electrically connected to the first winch assembly 50 and the second winch assembly 60 for actuation of respective motors in either a forward or reverse direction. This electrical connection may be with wires or wirelessly via transmitter/receiver technology, Bluetooth, or the like.

In yet another aspect and one related to safety, the present invention includes at least a pair of safety latches 74 (FIG. 6b ). Each safety latch 74 includes a shape configuration at one end complementary to a configuration of a ladder rung, the safety latch 74 having a spring mechanism that will prevent downward movement of the platform 40 relative to the end portions unless first released or the latch is first moved upwardly. As shown in FIG. 6a , respective safety latches 74 may be mechanically coupled to the controller 72 with a linkage 76.

In another aspect, a plurality of wheels 80 may be operatively coupled to a bottom of the framework 12 (base) described previously. Preferably, each wheel a castor type of wheel and each is rotatably coupled to a corner of the framework 12 so that the base, and therefore the scaffold lift apparatus 10, is mobile and easy to position.

In use, a worker may climb aboard the platform 40 by climbing respective rungs of a ladder end portion and begin painting or whatever construction is being undertaken using the scaffold. Then, when the worker needs to reach higher, there is no need to climb down and work with another person to make the scaffolding taller and move the platform to a greater height; instead, the worker may simply press the “Up” button on the controller to energize both pulley assemblies 50, 60 and, as a result, the platform 40 is raised as desired—and held securely by the pulley assemblies and also by respective safety latches 74, as described above.

It is understood that while certain forms of this invention have been illustrated and described, it is not limited thereto except insofar as such limitations are included in the following claims and allowable functional equivalents thereof. 

1. A lift apparatus for raising or lowering a worker on a scaffold, said lift apparatus comprising: a ladder assembly that includes: a first ladder end portion having a first fixed section and a first variable section movably coupled to said first fixed section and movable between lowered and raised configurations; a second ladder end portion having a second fixed section and a second variable section movably coupled to said second fixed section and movable between lowered and raised ladder configurations; a platform slidably coupled to said first ladder end portion and said second ladder end portion and slidably movable between lowered and raised platform configurations; a first winch assembly that includes: a first winch motor and a first spool electrically connected to said first winch motor; a first pulley coupled to said first variable section of said first ladder end portion; a first cord having a proximal end operably coupled to said first spool and a distal end coupled to said platform, said first cord extending about said first pulley for raising or lowering said platform when said first winch motor is energized.
 2. The lift apparatus as in claim 1, further comprising: a second winch assembly that includes: a second winch motor and a second spool electrically connected to said second winch motor; a second pulley coupled to said second variable section of said second ladder end portion; a second cord having a proximal end operably coupled to said second spool and a distal end coupled to said platform, said second cord extending about said second pulley for raising or lowering said platform when said second winch motor is energized.
 3. The lift apparatus as in claim 1, wherein said platform includes: a floor surface having a planar configuration; a platform first end portion having a first pair of upstanding support members mounted to an end of said floor surface and having a first plurality of rungs extending in parallel to one another between said first pair of upstanding support members, respectively; a platform second end portion having a second pair of upstanding support members mounted to another end of said floor surface and having and a second plurality of rungs extending in parallel to one another between said second pair of upstanding support members, respectively; a platform front section extending between said platform first end portion and said platform second end portion, said platform front section including at least one front support rail extending between respective upstanding support members of said first and second platform end portions; a platform rear section opposite said platform front portion and having at least a rear support rail extending between respective upstanding support members of said first and second platform end portions.
 4. The lift apparatus as in claim 3, wherein said platform front section includes a gate member having a distal end releasably coupled to said front support rail and movable between a closed configuration inline with said front support rail and an open configuration displaced from said front support rail so as to permit ingress or egress of worker relative to said platform.
 5. The lift apparatus as in claim 3, wherein: said first fixed section of said first ladder end portion includes a first upstanding leg and a second upstanding leg spaced apart from and parallel to said first upstanding leg, said first fixed section of said first ladder end portion having a plurality of rungs extending between said first and second upstanding legs of said first fixed section; and said second fixed section of said second ladder end portion includes a first upstanding leg and a second upstanding leg spaced apart from and parallel to said first upstanding leg, said second section of said second ladder end portion having a plurality of rungs extending between said first and second upstanding legs of said second fixed section.
 6. The lift apparatus as in claim 5, wherein: said first variable section of said first ladder end portion includes a first upstanding leg and a second upstanding leg spaced apart from and parallel to said first upstanding leg, said first variable section of said first ladder end portion having a plurality of rungs extending between said first and second upstanding legs of said first fixed section; and said second variable section of said second ladder end portion includes a first upstanding leg and a second upstanding leg spaced apart from and parallel to said first upstanding leg, said second variable section of said second ladder end portion having a plurality of rungs extending between said first and second upstanding legs of said second variable section.
 7. The lift apparatus as in claim 5, wherein: one corner of said floor surface of said platform is slidably coupled to said first upstanding leg of said first fixed section of said first ladder end portion with an alignment bracket that surrounds said first upstanding leg of said first fixed section in a friction fit arrangement; another corner of said floor surface of said platform is slidably coupled to said first upstanding leg of said second fixed section of said second ladder end portion with another alignment bracket that surrounds said first upstanding leg of said second fixed section in a friction fit arrangement.
 8. The lift apparatus as in claim 1, wherein said floor surface of said platform is slidably coupled to said first ladder end portion and second ladder end portion with alignment brackets, respectively.
 9. The lift apparatus as in claim 1, wherein: said first variable section is coupled to said first fixed section of said first ladder end portion in a telescopic construction, said first variable being telescopically adjustable between said lowered and raised configurations relative to said first fixed section; said second variable section is coupled to said second fixed section of said second ladder end portion in a telescopic construction, said second variable being telescopically adjustable between said lowered and raised configurations relative to said second fixed section.
 10. The lift apparatus as in claim 2, further comprising a controller electrically connected to said first and second winch motors, said controller having controls for actuating said first and second winch motors in a first direction and a second direction corresponding to raising or lowering said platform, respectively.
 11. The lift apparatus as in claim 1, further comprising a controller electrically connected to said first winch motor, said controller having controls for actuating said first winch motor in a first direction and a second direction corresponding to raising or lowering said platform, respectively.
 12. The lift apparatus as in claim 1, further comprising: a framework having a front brace and a rear brace opposite and parallel to said front brace and having a first side brace and a second side brace opposite and parallel to said first side brace, said first and second side braces extending between proximal and distal ends of said front and rear braces, respectively; wherein a lower end of said first ladder end portion is coupled to said first side brace and extends upwardly from said framework; wherein a lower end of said second ladder end portion is coupled to said second side brace and extends upwardly from said framework.
 13. The lift apparatus as in claim 5, further comprising: a framework having a front brace and a rear brace opposite and parallel to said front brace and having a first side brace and a second side brace opposite and parallel to said first side brace, said first and second side braces extending between proximal and distal ends of said front and rear braces, respectively; a plurality of support pocket fasteners mounted atop said front, rear, first side, and second side braces, respectively, each support pocket fastener defining an open top and an interior area for receiving a lower end of said first upstanding leg of said first fixed section, said second upstanding leg of said second fixed section, said first upstanding leg of said second fixed section, and said second upstanding leg of said second fixed section, respectively.
 14. The lift apparatus as in claim 13, wherein said each support pocket fastener includes a spring-loaded locking assembly that is automatically locked when a respective upstanding leg is received into a respective interior area.
 15. The lift apparatus as in claim 12, further comprising a plurality of wheels rotatably coupled to a bottom said of said framework such that the lift apparatus is mobile.
 16. The lift apparatus as in claim 3, further comprising at least one ladder lock pivotally coupled to an associated rung of said first plurality of rungs of said platform first end portion and another at least one ladder lock pivotally coupled to an associated rung of said platform second end portion, each ladder lock having a spring element and a configuration that prevents downward movement of said platform until released. 